Also in this week's column:
Why are some people more attractive to mosquitos?
Does eating fish improve brain function?
How can objects in the same room be different temperatures?
What is a Cro-Magnon man?
Asked by Nikki Jackson of Mosman, NSW, Australia
Cro-Magnon humans are regarded as the earliest form of modern humans. …

COMMENTS

In theory...

I believe the content of this article should be qualifed with "According to the theory of evolution..." I do not believe it has been scientifically proven that anyone or anything actually lived on this earth ten to forty thousand years ago. If so, how 'bout a reference?

re: In theory

If there is a better theory for the suspiciously human bone shaped rock formations that have been found (and dated to that period using some less controversial theories), I would like to hear it! All science is, by the very nature of the subject, in doubt, however for the sake of an easy to read article the writer should not have to add "according to the theory of whatever" to the beginning of every explanation. By the question referring to an early human, it was inherent in the article that the theory of evolution was assumed to be true.

On a slightly less reasonable note, I do not believe that it has been scientifically proven that you lived on this Earth at any time in the past, and yet we can still refer to you without quoting the "theory of people existing" (and if you think that that is a given, talk to a philosophy student for a half hour or so!).

Err.... not quite!

"Cro-Magnon humans are regarded as the earliest form of modern humans."

Err... not quite! Modern humans first appeared in Africa around 120 to 150 thousand years ago, according to the current dominant "Out of Africa" hypothesis of human evolution. Cro-Magnon man (and woman, of course) are the first representatives of our species in Europe, but they are not the earliest form of modern humans and nor are they regarded as such.

I've just realised...

... that the author of this is an anthropologist! And currently working in Australia! Consider the following.

Australian aborigines are estimated to have arrived in Australia anything between 120,000 to 50,000 years ago. If, as the author maintains, Cro-Magnon man was the first example of modern humans and didn't appear until about 40,000 years ago then this implies that Australian Aborigines are not modern humans. And nor, for that matter, are modern Africans who appeared in Africa around 150,000 years ago (the estimates vary).

The author has made some very entertaining howlers in other subjects but to make such a blunder in his own subject takes quite some doing.

Aboriginal Australians

Various ludicrous estimations by various sensationalist and less-than-rigorous scientists have indeed been made.

In fact, the first humans to arrive in Australia (and not necessarily related to the people we know now as "aboriginal") arrived in about 49,000BC, and were displaced by subsequent migrations over the following millenia.

The humans we know now as Australian "aboriginals" arrived in about 8000BC.

As for the "theory" of evolution - evolution is a fact, the "theory" part of it concerns our various suppositions as to its precise mechanism(s).

Think "gravity" - it is also a fact, but we (try to) explain it with the "theory" of gravity.

The idea that the earth is less than 10,000 years old is about a million miles short of the intellectual coherence and honesty required to form a theory and so remains a vague superstition.

Between a fact (evolution) and the theory that tries to explain it, and a vague superstition, I know which one to choose, and so does any other intelligent human being.

Humans in Australia

The situation regarding human migration to Australia is not as clear cut as that. There are both archaelogical and mitochondrial DNA datings that suggest anatomically modern humans arrived in Australia at least 60,000 years ago (cf. Cro-Magnon 40,000 to 10,000 ka.). Other human migrations have arrived since then but the evidence is not that they simply displaced all the previous inhabitants but, like the majority of known human migrations, interbred with them. Evidence from mitochondrial DNA suggests that Australian Aborigines, modern humans, have a very old lineage. (See PNAS | January 16, 2001 | vol. 98 | no. 2 | 537-542). While there are certainly many different strands of the modern human family within Australian Aborigines the evidence suggests that Australian Aborigines do not appear to be all direct descendants of humans who arrived 8,000 years ago but have a common lineage in Australia going back much further than that.

The point that we are not all descended from Cro-Magnon humans is even more pertinent to people of African origin. Cro-Magnon humans are European so while we all share a common lineage pre 40,000 ka. the evidence suggests that modern Africans are not direct descendents of Cro-Magnons.

The debates about exactly where and when humans evolved and our exact lineage are complex and fascinating. And while there is broad agreement that modern humans are first seen in Africa, the evidence as to exactly what happened from then on is incomplete, hence the type of debate we're having about humans origins in Australia. However, to assert as the original article did, that we are all descended from Cro-Magnons who did not appear until 40,000 years ago is not supported by the evidence and is a surprising claim for an anthropologist to make.

On Fact and Theory

Sorry, but one cannot say that evolution is a "fact"; and the analogy with what we call gravity - i.e. things falling down - does not hold. We can witness things falling down in its entirity, and can develop theories about this fact such as gravitational force, curved space, gravitons, etc. However, we have not witnessed the phenomenon of life-as-it-is emerging from rocks and other space debris. Neither could it ever be possible. Thus it cannot be said to be a "fact" but rather an assumption.

Neither is it the only possible assumption: life, the universe and everything may have continued much as it is through all eternity, or a restless god may have built us 6,000 years ago (or 6,000,000,000 years ago) like a child building a house out of Lego bricks. Rejecting these implausible assumptions - the latter out-of-hand and the former with a furtive, sideways glance at Indian mythology - does not elevate the first assumption to the status of "fact".

The proper response to creationist nonsense is surely to point out that established theory is not a mere exercise in supposition but is our best knowledge, based on all the evidence available to us and on sound logic. It does not help to offer our own deeply-felt convictions as "fact".

A fact?

In response to Matthew,

You pre-suppose that evoltuion is true because you have a prior commitment to materialism. Evolution has not been proven as a fact and it is absurd to say that it has. Just because a view is widely held does not mean that it is fact. Basically what you are saying is that you have decided that evolution must be true so you are going to interpret any facts you find accordingly. If you believe that the earth is millions of years old then why can c14 be found in diamond samples all over the world? I find evolution harder to belive than creationism. Evolution says that the information in our DNA resulted from natural processes but natural processes have never been shown to produce information. Information cannot be produced from non-information, just like life is not observed to come from non-life.

Nonsense?

"...established theory is not a mere exercise in supposition but is our best knowledge, based on all the evidence available to us and on sound logic. It does not help to offer our own deeply-felt convictions as "fact"."

I do not see how evolution could be offered as the best interpretation of the evidence. The "facts" show that life does not come from non-life and information does not come from non-information. Evolution claims both of these. Evolutionists hang on to their beliefs despite the fact that repeatable observational science contradicts them.

Evolution and Life's Origins

Danny, just a quick word. The question of life's origin (presumably from inanimate chemicals) is separate from that of its subsequent evolution. On the latter the evidence and logic are abundant. I am convinced by it, though it is still our best understanding and not - strictly speaking - an incontrovertible fact.

On the former question, the field is wide open. This is not a question of evolution but of something else. Essentially you must choose between supposing a restless god built life somehow (how? - that still needs explaining) and supposing (sic) that it happened through (as yet poorly understood) natural processes - unless, of course, you prefer the eternal stasis idea.

incontrovertible fact?

Actually, I reject both ideas and I also reject that evoltuion is a proven fact. If you have a "proof" of evolution I would like to see it. (I realize that it is hard to debate in the comments section of an online article)

I believe in the history of the Bible and that God created the universe and all life in 6 literal days. I would love to debate with you but I am warry of posting my email address in an article that is viewable by the entire world.

Debate?

As for debate, I find your position somewhat ambiguous. On the one hand you say science has not enough "proof" - implying that with more substantial evidence you might agree with its conclusions, while on the other you say you find it easier to accept explanations in your sacred texts, which are entirely, and by their essential nature, unscientific. A person may prefer to take their notions from sacred texts rather than from research and reason - that is their choice. However, to accuse science of not being rigorous enough in its evidence while at the same time saying that you prefer unscientific sources is intellectually dubious. Which is it? Do you follow reason or faith?

You need to ask yourself these questions - and find an answer - before you can engage in any debate on the matter.

"Proof" of evolution...

Evolution is a theory, like most of the explanations in the sciences that deal with the past, it is likely to remain a theory (at least without detailed records from a civilization that exists for a few hundreds of millenia), however there is a body of evidence to suggest that it occurs, which has been drawn from direct observations.

Firstly, random mutations causing changes to an organism. In the negative side this could be cancer, or some genetic condition turning up in a person with no family history of that condition.

Secondly, natural selection. This can be seen in many instances, either by the slower of the gazelles being caught by the faster of the cheetahs, or by the oft-quoted example of the peppered moth (which I will not repeat here to save space. Various genetic experiments have proven beyond most doubt that characteristics can be passed on through generations, so it stands to reason that if a trait causes members of a species to survive, then it is more likely to be kept.

Some mutations will have both good and bad factors (such as the one that causes sickle cell anemia, which can provide a resistance to malaria), and therefore the trait will be more likely to be kept under certain stresses (i.e. an area with a high chance of catching malaria) and lost under others.

The simplest example of both these factors in action is in viruses, where mutations to the genes that code for the coating of a virus can make it undetectable by the immune system even if there is a resistance to the virus before the mutation.

While this does not prove that evolution did occur, it shows the mechanisms by which it might occur, and suggests ways for species to become separated (e.g. different beneficial mutations arising in separate populations of the same species).